U.S. patent number 9,851,145 [Application Number 14/333,276] was granted by the patent office on 2017-12-26 for radial counterflow reactor with applied radiant energy.
This patent grant is currently assigned to MCCUTCHEN CO.. The grantee listed for this patent is McCutchen Co.. Invention is credited to David J. McCutchen, Wilmot H. McCutchen.
United States Patent |
9,851,145 |
McCutchen , et al. |
December 26, 2017 |
Radial counterflow reactor with applied radiant energy
Abstract
An improvement is described for the processing of biological
material in a continuous stream by the application of radiant
energy taken from the wavelengths from infrared to ultraviolet, and
its absorption by a feedstock in a workspace of featuring
controlled turbulence created by one or more counter-rotating disk
impellers. The absorbed energy and the controlled turbulence
patterns create a continuous process of productive change in a feed
into the reactor, with separated light and heavy product output
streams flowing both inward and outward from the axis in radial
counterflow. The basic mechanism of processing can be applied to a
wide range of feedstocks, from the promotion of the growth of algae
to make biofuel or other forms of aquaculture, to a use in the
controlled combustion of organic material to make biochar.
Inventors: |
McCutchen; David J. (Portland,
OR), McCutchen; Wilmot H. (Orinda, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
McCutchen Co. |
Portland |
OR |
US |
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Assignee: |
MCCUTCHEN CO. (Portland,
OR)
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Family
ID: |
46577679 |
Appl.
No.: |
14/333,276 |
Filed: |
July 16, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140325866 A1 |
Nov 6, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13360564 |
Jan 27, 2012 |
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61437277 |
Jan 28, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C12P
7/64 (20130101); C12N 13/00 (20130101); C12N
1/12 (20130101); C12M 31/12 (20130101); C12M
21/02 (20130101); F26B 3/283 (20130101); C12N
1/066 (20130101); C12M 27/02 (20130101); A01K
61/59 (20170101); C12M 31/10 (20130101); C12M
27/10 (20130101); Y02A 40/824 (20180101); Y02A
40/81 (20180101); Y10T 137/206 (20150401) |
Current International
Class: |
C12M
1/02 (20060101); C12P 7/64 (20060101); C12N
13/00 (20060101); C12N 1/12 (20060101); C12N
1/06 (20060101); C12M 3/04 (20060101); C12M
1/06 (20060101); C12M 1/00 (20060101); A01K
61/59 (20170101); F26B 3/28 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2354462 |
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Mar 2001 |
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GB |
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2009142765 |
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Nov 2009 |
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WO |
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Other References
"All Biochar is Not Created Equally";
http://www.biocharsolutions.com/technology.html; printed on Feb.
13, 2012. cited by applicant .
Chen, C. et al., Cultivation, photobioreactor design and harvesting
of microalgae for biodiesel production: A critical review;
Bioresource Technology 102 (2011) 71-81. cited by applicant .
"Biochar Pathways for Different Environments"; International
Biochar Initiative, Aug. 26, 2009, pp. 1-2. cited by applicant
.
Mata, T. et al., Microalgae for biodiesel production and other
applications: A review; Renewable and Sustainable Energy Reviews 14
(2010) 217-232. cited by applicant .
Park, W. et al., Determination of Pyrolysis Temperature for
Charring Materials; National Institute of Standards and Technology,
U.S. Dept. of Commerce, NIST GCR-07-913, Dec. 2007. cited by
applicant .
Sheehan, J. et al., A Look Back at the U.S. Department of Energy's
Aquatic Species Program--Biodiesel from Algae; National Renewable
Energy Laboratory, NREL/TP-580-24190, Jul. 1998. cited by applicant
.
Shelef, G. et al., "Microalgae Harvesting and Processing" A
Literature Review; U.S. Department of Energy, Technion Research and
Development Foundation Ltd.; SERI/STR-231-2396, Aug. 1984. cited by
applicant .
Ugwu, C. U. et al., "Photobioreactors for mass cultivation of
algae"; Bioresource Technology 99 (2008) 4021-4028. cited by
applicant .
Zellwerk GmbH, "Cells Working for You"; retrieved at
http://www.glenmills.com/index-z.sub.--rp.shtml; printed on Dec.
29, 2010. cited by applicant .
"Algaewheel Brochure", retrieved at http://www.algaewheel.com
(2012). cited by applicant .
International Search Report dated May 16, 2012 corresponding to
International Application No. PCT/US2012/023021. cited by
applicant.
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Primary Examiner: Beisner; William H
Attorney, Agent or Firm: Marger Johnson
Parent Case Text
APPLICATION HISTORY
This application is a divisional of co-pending U.S. patent
application Ser. No. 13/360,564, filed Jan. 27, 2012, which claims
the benefit of U.S. Provisional Patent Application No. 61/437,277
filed Jan. 28, 2011.
Claims
The applicants claim:
1. A radial counterflow apparatus with radiant energy applied to
the transformation of a feed, comprising: a source of radiant
energy in a wavelength from infrared to ultraviolet; two
counter-rotatable disk impellers with a common axis of rotation,
defining a workspace between them, the disk impellers being at
least one of optically transparent or thermally conductive to the
radiant energy, at least one impeller having an output deflector
wall; a baffle disposed between said two coaxial counter-rotatable
disk impellers; an axial feed port approximately centered on said
axis of rotation, disposed underneath the baffle, and communicating
with the workspace; a feed transport communicating with the axial
feed port; a heavy products exhaust port located on the periphery
of the workspace to receive heavy products including any heavy
products deflected from the deflector wall; an axial exhaust port
approximately centered on said axis of rotation, disposed above the
baffle, and communicating with the workspace; an axial suction pump
communicating with the axial exhaust port; a drive wheel to cause
counter-rotation connected to the disk impellers, and a feed.
2. The apparatus of claim 1, wherein the radiant energy comprises
visible light, and at least one of said disk impellers comprise a
transparent portion adjacent the workspace.
3. The apparatus of claim 1, wherein the source of radiant energy
comprises an infrared source embedded in at least one of said disk
impellers being conductive to the radiant energy.
4. The apparatus of claim 1, wherein said disk impellers narrow in
separation toward the periphery of the workspace.
5. The apparatus of claim 1, wherein said disk impellers comprise
vanes extending into the workspace, the vanes of the disk impellers
being disposed in opposition across the workspace.
6. The apparatus of claim 1, wherein said disk impellers comprise
rugose ridges, the rugose ridges of the disk impellers being
disposed in opposition across the workspace.
7. The apparatus of claim 1, wherein at least one of said disk
impellers comprises an annular crossflow filter.
8. The apparatus of claim 1, wherein said baffle comprises vanes
extending into the workspace.
9. The apparatus of claim 1 wherein the peripheral drive wheel
contacts both of the two counter-rotatable disk impellers.
10. The apparatus of claim 1, wherein the feed comprises algae,
water, carbon dioxide and nutrients.
11. The apparatus of claim 10, wherein lipids are extracted through
the axial exhaust port by the axial suction pump.
12. The apparatus of claim 1, wherein the drive wheel comprises a
straight bevel gear.
13. The apparatus of claim 1, wherein the drive wheel comprises a
spiral bevel gear.
14. The apparatus of claim 1, further comprising a drive track to
connect to the drive wheel.
15. The apparatus of claim 1, further comprising sleeper wheels.
Description
FIELD
The present disclosure is related to drying and gas or vapor
contact with solids, by continuous processing with centrifugal
force and heating; cleaning and liquid contact with solids with
means for collecting escaping material; classifying, separating and
assorting solids, with heat treatment; classifying, separating and
assorting solids with fluid suspension with grading deposition of
gaseous feed with fluidically induced, unidirectional swirling; or
classifying, separating and assorting solids, with a liquid feed
grading deposition including rotational hydrodynamic extraction;
and pumps where one fluid is pumped by contact or entrainment with
another within a rotary impeller, or by a jet.
BACKGROUND
The separation of the products of a reaction taking place within a
feedstock is currently done in several ways. Examples include batch
processing, gravity separation, and centrifugal separation. A new
approach is a radial counterflow reactor, which uses a feedstock in
a workspace with controlled turbulence patterns created by the
rotation of one or more disk impellers, and is described in several
disclosures by the present applicants.
There are currently a variety of vessels for the growth or other
processing of biological material. The current approaches do not
allow for the efficient application of energy throughout the
material within the vessel, while simultaneously stripping out
exceptionally beneficial or harmful components within the vessel in
a continuous process which lends itself to high volume.
Two examples will be used here to illustrate this. The first is the
promotion of algae growth for the production of biofuels from
CO.sub.2. Typically the algae is placed with sterilized water and
nutrients in clear vessels such as tubes to allow sunlight to shine
in, and CO.sub.2 is bubbled up in the tubes to mix with the algae.
There is inefficiency in the application of the sunlight energy to
the tube, where much of the algae in the interior of the column are
shielded from the sun while that on the exterior may get too much.
A need exists for improved access of light for photosynthesis to
algae in a bioreactor or in a pond.
The distribution of the CO.sub.2 in the tube also tends to be
uneven because there is not enough mixing. When the algae has had
time to create oils and other hydrocarbons, which here will be
generally called lipids, then the algae has to be extracted, dried,
and processed to remove the lipids. This is a wasteful and energy
intensive extra step, and because this is a batch process, there is
not a continuous stream that would lend itself to high volume.
It would be preferable to have a continuous lipid production
process that did not depend on killing the algae. A goal of
research has been to engineer a "lipid trigger" in the algae to
make it extrude lipids, instead of storing them internally, and to
do so continuously, instead of only producing them intermittently
during periods when there is no cell division. But if a live algae
colony were able to be continuously producing lipids in this way,
there is no efficient way to extract the lipids to keep them from
contaminating the algae environment. There is also no way to, at
the same time, continuously separate the dead algae from the live
ones, to keep the most productive members flourishing. Also, there
is a need to strip out the oxygen produced by the algae to favor
the forward photosynthesis reaction for enhancing algae growth.
Where algae is in a pond, oxygen is produced by photosynthesis and
released to the atmosphere, but dissolved oxygen in the water is
consumed by the decay of dead algae, and the depletion of oxygen in
the water leads to dead zones where fish cannot live.
In shrimp and fish aquaculture, oxygen is desired, instead of
carbon dioxide, but the same need exists for continuous stripping
of waste gases and circulation of water to extract feces and other
waste material.
To use another example, the combustion of material to create
biochar is typically done in furnaces in a batch process. There is
a need for continuous mixing that ensures that heat energy will be
evenly applied throughout the feedstock, and for an efficient
mechanism for continuously stripping out volatile gases or liquids
to aid the forward reaction.
The applicants have described a variety of variations on the design
of a radial counterflow reactor comprising one or more rotating
disk impellers, which has many benefits in establishing a radial
counterflow pattern with lighter elements continuously migrating
toward the axis, and heavier elements toward the periphery. This
radial counterflow reactor idea has been described through its
application to the continuous processing of gases, liquids and
sludge.
SUMMARY
A radial counterflow reactor is described featuring radiant energy,
from among the wavelengths from infrared to ultraviolet, applied to
the workspace. The reactor typically comprises two approximately
parallel counter-rotating disk impellers, defining a turbulent
workspace between them. The workspace can also be defined by a
single impeller approximately parallel to a static casing. The disk
impellers are conductive to the radiant energy, allowing at least
some portion of the radiant energy to pass through them into the
workspace to transform the feed. The radiant energy can come from
emitting elements which are outside of the impellers and the
workspace, or the radiant energy can come from elements embedded in
the impellers.
One example design is a photobioreactor with two counter-rotating
disk impellers, defining a turbulent workspace between them. The
disk impellers are transparent to radiant energy, to allow an
applied radiant energy, from infrared to ultraviolet, to be
transmitted through them into the workspace to transform the feed.
This type of photobioreactor reactor is especially useful for the
growth and processing of biological and organic material, including
in aquaculture.
For example, algae can be grown between transparent disk impellers
in an axenic closed photobioreactor system, with improved means for
extraction of products such as lipids for oil production. The
impellers can be oppositely rotating solid disks, or moving liquid
disk layers created by an array of jets. The algae feedstock,
together with water, CO.sub.2 and nutrients, is fed into the
workspace and slowly sheared by the impellers, creating a fractal
network of branching vortices where controlled turbulence and
centrifugal force spins heavier components toward the periphery of
the vortices and toward the periphery of the disks. At the same
time, suction applied to the axial port in the upper disk impeller
by a suction pump draws the lighter products such as lipids inward
in a sink flow through the cores of the vortices, to be exhausted
out of the axial port. The transparent disk impellers can be solid
or liquid. If moving liquid disk layers form the impellers, they
can contain dissolved nutrients or gases to be supplied by
diffusion to the workspace, and they can also carry away wastes
through drains in the impeller layers. In addition, the liquid
impeller layers can supply hot or cool water as needed. Dead algae
sink and are swept to the periphery of the photobioreactor where
they are extracted as a sludge. Continuous gentle churning of the
algae in this way exposes more of them to the light and extracts
the waste products.
In an embodiment for shrimp farming, algae and shrimp may coexist
in the photobioreactor such that the shrimp eat the algae. Dead
shrimp and feces are spun out by the disk impellers while live
shrimp thrive among the live algae being nourished at the center.
Methane and other waste gases are stripped out continuously and
oxygen is introduced along with the recycled water.
In an embodiment for fish farming, feces and dead fish are spun to
the periphery of the photobioreactor where they can be easily
collected at a wall, while the water is extracted, clarified,
degassed, and aerated prior to being reintroduced to the tank.
In another example design, biological and organic material is
processed by radiant energy coming out of the solid impellers in a
biochar reactor where wood or other organic waste is pyrolyzed by
heat applied through heated impellers, with biochar accumulating at
the periphery, and bio-oil and gases exhausted out of the axis.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cross section of a radial counterflow reactor
utilizing absorbed energy applied into a feedstock, showing the
basic components, as well as the flow of a feedstock and energy
into it, and the flow of byproducts out.
FIG. 2 shows a close-up of a portion of the reactor shown in FIG.
1, with more detail for the workspace.
FIG. 3 shows a schematic side view of the flow patterns in the
workspace.
FIG. 4 shows a head-on view of the flow patterns in the workspace,
featuring nested vortices.
FIG. 5 shows a top view of the bottom disk impeller, showing the
ports, vanes and other components.
FIG. 6 shows a side cross section view of the bottom disk impeller
shown in FIG. 5.
FIG. 7 shows the superimposed patterns of the vanes for the top and
bottom impellers, at a starting point in their
counter-rotation.
FIG. 8 shows the superimposed patterns of the vanes for the top and
bottom impellers, rotated by 10.degree. in opposite directions.
FIG. 9 shows the superimposed patterns of the vanes for the top and
bottom impellers, rotated by 20.degree. in opposite directions.
FIG. 10 shows the superimposed patterns of the vanes for the top
and bottom impellers, rotated by 30.degree. in opposite
directions.
FIG. 11 shows the superimposed patterns of the vanes for the top
and bottom impellers, rotated by 40.degree. in opposite
directions.
FIG. 12 shows the superimposed patterns of the vanes for the top
and bottom impellers, rotated by 50.degree. in opposite
directions.
FIG. 13 shows the superimposed patterns of the vanes for the top
and bottom impellers, rotated by 60.degree. in opposite
directions.
FIG. 14 shows the superimposed patterns of the vanes for the top
and bottom impellers, rotated by 70.degree. in opposite
directions.
FIG. 15 shows the superimposed patterns of the vanes for the top
and bottom impellers, rotated by 80.degree. in opposite
directions.
FIG. 16 shows a set of flows for a radial counterflow algae
photobioreactor.
FIG. 17 shows a set of flows for a radial counterflow biochar
bioreactor.
FIG. 18 shows a top view of an array of jets to create a moving
liquid disk impeller.
FIG. 19 shows a cross section of two liquid impellers in a
photobioreactor for aquaculture.
DRAWING REFERENCE NUMERALS
1--feed source 2--feed transfer 3--axial feed conduit 4--axial feed
port 5--baffle 6--bottom disk impeller 7--top disk impeller
8--rotation of top disk impeller 9--rotation of bottom disk
impeller 10--axis of rotation 11--workspace 12--periphery of the
workspace 13--heavy products exhaust port 14--heavy products
collection 15--heavy products transfer 16--heavy products storage
17--sink flow 18--axial exhaust port 19--axial suction pump
20--lighter products transfer 21--lighter products receptacle
22--axial support shaft 23--upper exhaust conduit 24--upper disk
bearing and seal 25--lower intake conduit 26--lower disk bearing
and seal 27--base support 28--prime mover 30--lower drive track
31--upper drive track 32--support wheel 33--sleeper wheel
34--sleeper wheel support 35--drive shield wall 36--output
deflector wall 37--output vent 38--heavy product screw conveyor
39--pinch section 40--pinch opening 41--radiant energy source
42--absorption into feed 45--axial feed pump 46--feed flow 47--sink
flow 48--heavy products flow 50--vortex in shear layer 51--vane on
lower disk 52--vane on baffle 53--vane on upper disk impeller
54--crossflow filter inset into bottom disk impeller 55--liquid
flow through crossflow filter 56--rugose ridges on bottom disk
impeller 56a--gas vent on top disk impeller 57--rugose ridges on
top disk impeller 60--boundary layer 61--direction of flow of
boundary layer 62--flow from boundary layer to shear layer
63--shear layer 64--outer part of vortex 65--direction of flow of
outer vortex 66--movement from shear layer to boundary layer
67--inner part of vortex 68--direction of flow of inner vortex
69--inward sink flow 70--vortex with counterclockwise rotation
71--vortex with counterclockwise rotation 72--centrifugal
separation 73--bottom impeller 74--first vane 75--second vane
76--third vane 77--fourth vane 78--edge of baffle 79--conical apex
of screw feed conveyor 80--vane crossing intersection
81--corresponding inverted vane on top disk impeller 82--first
intersection axis 83--second intersection axis 84--third
intersection axis 85--fourth intersection axis 86--fifth
intersection axis 87--sixth intersection axis 88--seventh
intersection axis 89--eighth intersection axis 90--rugose ridge on
bottom disk impeller 91--example of corresponding inverted rugose
ridge on top disk impeller 92--gas vent 93--drive shield wall brace
96--straight vane on bottom impeller 97--straight vane on top
impeller 98--heavy products flow 99--light products sink flow
100--vortex network 101--main supply pipe 102--branch supply pipe
103--liquid jet nozzle 104--area of jet 105--direction of flow
106--drain inlet 107--drain pipe 108--central drain 109--central
supply pipe 110--axial exhaust 111--support frame 112--support
float 113--peripheral wall 114--upper liquid impeller 115--lower
liquid impeller 116--turbulence flow 117--nutrients 118--waste
products in liquid impeller 119--supply inlet 120--drain outlet
DETAILED DESCRIPTION
Three examples will be given of a radial counterflow reactor with
radiant energy applied to the feed. Each comprises a closed vessel
with one or more feed stock input ports, one or more output ports
for lighter products, and one or more output ports for heavier
products, plus a source of radiant energy, in wavelengths selected
from infrared to ultraviolet, to be to be absorbed by the
feedstock. The first example will describe a photobioreactor with
solid impellers. The second example describes a more simplified
photobioreactor with liquid impellers. Both of these examples use
radiant energy transmitted through transparent impellers. The third
example is a biochar processor which also uses solid impellers,
which are heated, either by the application of external heat or
internal heating elements.
Algae Processor
This reactor will first be described in an exemplary configuration
as a photobioreactor for growing lipid-producing algae. It will be
appreciated by the skilled practitioner that this example is not
meant to restrict the possible applications of this description to
the solution of other types of problems. Similarly, the design
disclosed here is exemplary, and is not meant to preclude any
modified design to suit a particular purpose.
A feed source 1 comprises storage for a transportable feed, such as
algae, combined with water, CO.sub.2, and nutrients. A feed
transfer 2 brings the feed into the photobioreactor, by means such
as pumps, conveyors or a gravity feed, into an axial feed conduit
3, leading to an axial feed port 4, where the feed enters the
photobioreactor in a space underneath a baffle 5, which is located
between a bottom disk impeller 6 and top disk impeller 7. These two
disk impellers, which act as centrifugal pumps, rotate in opposite
directions, such as those shown at 8 and 9, about an axis of
rotation 10. A workspace 11 is defined in the space between the
disk impellers. The workspace has boundary layers along the
surfaces of the impellers, and a shear zone between the boundary
layers, where amplified centrifugal force in organized vortex
turbulence creates separation between the heavy and lighter
products.
After the algae is introduced into the photobioreactor, it is
expected to multiply and grow there within it, and the primary feed
from then on will be water along with CO.sub.2 and nutrients to
promote proper growth.
The heavier products, such as an algae sludge, move toward the
periphery of the workspace 12 where they are extruded, falling
through a heavy products exhaust port 13 to be collected, in this
case into an annular heavy products collection trough 14, where the
heavy products transfer means 15 convey the heavy products to the
heavy products storage 16. Meanwhile, while the heavy products
migrate outward, an inward sink flow 17 is set up above the baffle,
leading inward to an axial exhaust port 18. The sink flow is forced
by an axial suction pump 19, in this case a screw conveyor. This
pump can also be a mechanical pump or any other kind of appropriate
pump to draw out the light products axially so a lighter products
transfer 20 can convey them to a lighter products receptacle 21.
These lighter products include anything with a lower specific
gravity than the heavier products. For example, the lighter
products can include lipids extruded by the algae and oils as well
as gases including oxygen produced by photosynthesis.
The disks and the conveyor pumps in this design are supported by an
axial support shaft 22, which extends downward through the upper
exhaust conduit casing 23. This casing has the support for the
upper disk bearing and seal 24, which preferably contains a
combination thrust bearing and rotary seal. A similar disk bearing
and seal is in the casing for the lower disk. If the disk bearing
and seal 24 is made to be movable up and down, such as by a
telescoping upper exhaust conduit casing 23 and/or a similar one
for the bottom disk impeller, then the separation between the top
and bottom disk impellers 7 and 6 can be changed if needed. For
instance, in the example of algae, a relatively wide separation
could be used for an algae growth process, and a narrower one could
be used to concentrate and dewater a resulting algae sludge. The
axial support shaft 22 preferably also extends down through the
axial feed conduit 3, which has an axial feed pump 25, in this case
a screw conveyor, and lower disk bearing and seal 26. Because these
screw conveyors are tied to the disk impeller motion and the disk
impellers have opposite rotation 8 and 9, the screw conveyors in
this design have an opposite slope in order to make a consistent
movement of material upward in both cases. A base support 27
anchors the assembly.
On the periphery of the disks is a prime mover 28 to turn the disk
impellers in counter-rotation. This prime mover 28 can be a motor
or another source of motive power such as wind or water power. The
motor can be coupled to the hub or another part of the disk
impellers in order to turn them. In this instance, the prime mover
is coupled to a peripheral drive wheel 29 which simultaneously
contacts the bottom disk impeller 6 at a bottom drive track 30, and
the top disk impeller 7 at a top drive track 31. The rotation of
the drive wheel 29 would therefore turn the two disk impellers in
opposite directions. The drive wheel would preferably be a straight
or spiral bevel gear, and the drive tracks would be compatible gear
tracks. Support wheels such as at 32 contacting the opposite side
of the disk impeller from the drive tracks will help to maintain a
consistent engagement of the drive wheel 29 with the drive track
such as at 30. Sleeper wheels such as at 33 also maintain a
consistent separation of the disks, and are supported by sleeper
wheel supports such as at 34.
Inboard of the drive wheels are barrier walls to shield the drive
components from the products inside, and to direct their flow. The
drive shield wall 35 is an annular wall attached to the top disk
impeller, and is a backup barrier to prevent the products from the
interior of the photobioreactor from clogging the drive system.
Inboard of the drive shield wall 35 is the output deflector wall
36, which is also an annular wall, but this time attached to the
bottom disk impeller, and angled inward so that the outward flow
from the periphery is deflected downward to the heavy products
exhaust port 13 and the heavy products collection trough 14. On the
top of this output space, an output vent 37 allows remaining gases
from the heavy product to escape. The collection trough 14 for the
heavy product can contain a conveyor to further collect it, such as
an annular heavy product screw conveyor 38 in the bottom of the
trough, ending in a tangential branch for dumping the product into
a hopper.
Inboard of these barrier walls, the separation of the disks narrows
to the pinch section 39, where heavy output products are squeezed
and concentrated, beginning with the pinch opening 40, where the
workspace narrows.
The passage of feed into the workspace, while the disk impellers
are in motion, creates a fractal network of vortices in the shear
layer, with lighter products converging in a sink flow 17 into the
axial exhaust port 18. At the same time, radiant energy, selected
from the range of wavelengths from infrared to ultraviolet, is
transmitted by a radiant energy source 41, so that it is absorbed
into the feed 42 in the workspace.
This radiant energy transmission is done by making the disk
impellers transparent or conductive to the radiant energy. For this
example of an algae photobioreactor, the transparent disks allow
the energy from sunlight or other artificial light energy to pass
through them into the feed to be absorbed, including the
wavelengths most beneficial for algae growth.
If the algae can benefit from the maximum amount of exposure to
light, it is preferable for both disk impellers 6 and 7 to be
transparent, and for there to be a light source both above and
below the disks. This can be done with a reflector for a single
light source such as the sun, or with duplicate artificial light
sources above and below the disks. If the photobioreactor described
here is duplicated in a stack, then the light source for the bottom
of one photobioreactor can serve as the light source for the top of
another. As an alternative, a single light source can be reflected
back into the feed from a mirror finish on the disk impeller
opposite the transparent disk impeller.
As the disk impellers slowly turn, the algae in the workspace are
slowly swirled and rotated in the vortex flows, being exposed to
light from every side, and continuously absorbing energy, like a
roast being rotated on a spit. Heat flux due to forced convection
sweeping the heat transfer surfaces is 50 W/cm2 which is better
than static heating (pool boiling) at only 20. Controlled agitation
of the algae maximizes the energy flux into them. This controlled
agitation also provides radially inward pathways for the extraction
of oxygen from photosynthesis, ammonia, H2S, oil, and clean water
through the axial exhaust port 18, here shown as an opening at the
center of the top disk. The axial extraction of light fractions
enables a continuous process which favors photosynthesis by
extracting the products.
The disk impellers may be solid transparent disks, screens, radial
arms, or other configurations and materials permitting flux of
radiant energy into the workspace. Ultraviolet radiant energy can
thus have enhanced disinfecting by churning the feed so that
microbes are exposed and killed by UV because suspended solids
offer them no effective shade.
FIG. 2 shows a close-up of the left side of the workspace 11 in
FIG. 1. The feed flow into the photobioreactor is shown at 46, and
the sink flow for light products to axial extraction out of the
photobioreactor is shown at 47, as well as the peripheral flow
outward for heavy products 48. The feed in the axial feed conduit 3
comes through the axial feed port 4 and enters the photobioreactor
in the space underneath the baffle 5, which is located between the
bottom disk impeller 6 and the top disk impeller 7. The feed flow
is enhanced by vanes attached to the impellers, such as those shown
in FIGS. 7-15. The vanes on the bottom impeller are indicated by
51, the vanes on the baffle are at 52, and the vanes on the upper
impeller are shown at 53. In this example, the baffle is assumed to
be attached to the bottom disk impeller so they co-rotate, so the
vane pattern of the vanes on the top of the baffle 52 will resemble
the vanes on the bottom impeller 51.
An optional crossflow filter 54 inset into the bottom disk impeller
can be used to remove fluid from a sludge in a fluid flow 55, by
making use of the force produced when the sludge is forced outward
by centrifugal force while being squeezed by the pinch section 40
where the disks impellers have a narrower separation. The crossflow
filter is a sintered metal or plastic screen, made flush to the
interior surface of the disk impeller facing the workspace, and
usually backed by a watertight plug to close it when it is not in
use. This crossflow filter would be used for dewatering an algae
sludge, with the disk impellers spinning much faster than they
normally would for general algae growth. This faster rotation would
tend to spin all of the algae outward from the workspace, to clear
the way for a fresh batch. The dewatered algae sludge concentrate
would then proceed outward into the pinch section 40.
A similar perforated opening gas vent 56a in the top disk impeller
could be used to vent gases that would tend to accumulate in
bubbles on its interior surface, and be swept out toward the
periphery by the vanes. There would be a smaller net area of
opening needed for the vent in this case. The vented gases should
be monitored as to their composition, as part of the sensors which
would monitor the condition of the feed in the workspace, measuring
factors such as temperature, pH, density, nutrients and mass
flow.
Optional rugose ridges, such as 56 on the bottom impeller and 57 on
the top impeller, can interrupt and constrict the outward flow 48
flow still further, causing pressure waves for osmotic shock at low
speed or cavitation in fluids at high speed, as another way to
transform the feed. These rugose ridges are described more fully in
the discussion of FIG. 5.
FIG. 3 shows a cross section close-up of the flows in the
workspace. Next to each disk impeller 6 and 7 is a boundary layer
60, characterized by a laminar flow 61 of the feed, some of which
flows inward 62 to the shear layer 63, which is located between the
boundary layers. The shear layer contains a branching
area-preserving network of vortices, with larger vortices toward
the axis collecting the products of smaller vortices toward the
periphery. The outer region of a typical vortex is shown at 64,
with its flow at 65. Heavier products are spun out by amplified
centrifugal force in the photobioreactor and migrate outward, first
to the outer regions of the vortex and then to the boundary layer
in an outward flow 66. Meanwhile, the inner part of the vortex 67
has a flow 68 that collects the lighter parts, which are drawn
inward toward the axis of rotation in a sink flow 69.
In the case of algae, under normal growth conditions the boundary
layers would comprise mostly a water, CO.sub.2 and nutrient feed,
and the algae would concentrate in the vortices in the shear layer,
where they would divide and grow.
FIG. 4 shows an orthogonal cross section of the workspace, with a
flow pattern of vortices, where the clockwise flow of a larger
vortex 70 may be surrounded by counterclockwise flows 71 in the
overall turbulence pattern. Both of these types of vortices
contribute to the overall sink flow network by creating centrifugal
separation 72 of the feed. For algae, the rotations of the algae in
these vortices would expose all of them more completely to the
light coming through the disk impellers, while at the same time the
centrifugal separation 72 would strip out the products with a lower
specific gravity, such as extruded lipids, into the sink flow.
Recent work by VG Energy has shown how the lipid trigger can be
manipulated to make algae overproduce and extrude lipids, instead
of storing them in their bodies. If these extruded lipids can be
continuously stripped away from the algae, they will not
contaminate the environment of the algae and inhibit their growth.
The live algae are typically kept apart by electrical repulsion,
and kept buoyant by their motility as well as internal gas vacuoles
or gas bubbles on their membranes, but as they die they would
become less buoyant and would migrate into the heavier products
flow outward. Thus, the dead algae would tend to collect on the
periphery of the reactor, and the lighter products such as lipids
would be continuously collected in the axial sink flow.
If the goal of the photobioreactor is the mass production of algae,
then the excess algae be extruded at the periphery, leaving a
constantly growing and dividing stock in the workspace. This
separation could be assisted by the clumping of algae by
autoflocculation. As the algae consume the carbon dioxide being
introduced axially, the outer regions of the workspace grow to have
a higher pH, which, together with flocculants in the solution such
as calcium carbonates and calcium phosphates, cause the algae to
clump together. This increases the centrifugal force on the clumps,
and causes them to spin outward to the periphery. Using ports in
the disk impellers for introducing flocculant chemicals directly
into the solution at a given radial distance from the axis of
rotation 10 can allow more precise control of this process.
In FIG. 5 is a top view of the bottom impeller 73, which has a
clockwise rotation 9. It can be made of any suitable material, such
as plastic, glass, ceramic, metal or any practical material. In the
case of transparent disk impellers for algae, the material used
should not block the most beneficial wavelengths. There are, in
this example, four vanes 74, 75, 76 and 77, attached to the
impeller and made of a suitable material, shaped in this case
according to a spiral. The edge of the baffle 5 is indicated at 78.
In the center, at the axis of rotation, is the apex of the screw
feed conveyor 79, which preferably should be conical to produce a
more lateral feed underneath the baffle.
The vanes form crossing intersections such as 80 with the
corresponding but inverted vanes on the underside of top impeller,
such as 81, which is here seen as if looking down through the top
impeller at a moment when the vanes are crossing. These moving
intersections form a rhythmical flow along eight well-defined
intersection axes: 82, 83, 84, 85, 86, 87, 88 and 89. This
rhythmical flow is shown in FIGS. 7-15. The mass flow along these
eight axes is the basis for the organized turbulence of the flow of
the shear layer between the disks. This mass flow through the
boundary layers also prevents the formation of biofilm which can
coat the disk impellers and block light. The vanes push the feed
outward as the disk impellers turn, and the intersection points
moving outward along the intersection axes form moving zones of
increased shear and vorticity which reinforce the sink flow moving
inward toward the axis of rotation.
A pattern of rugose ridges 90 can be part of the peripheral
section, as also seen in FIG. 2. They are designed to intersect the
corresponding rugose ridges from the top impeller, such as shown by
a sample at 91. These rugose ridges are for causing osmotic
pressure waves at low speeds or cavitation in liquids at high
speeds, or to aid in the comminution of a more solid feed. In the
case of algae, the rugose ridges would produce osmotic shock, and,
at high speed, cavitation bubbles in the water, which would explode
the algae cell membranes and release the contents, allowing a
better interaction with digestive enzymes for more complete
recovery of any stored lipids.
The output deflector wall is shown at 36. This barrier, which can
be made part of the impeller or separately attached, deflects the
processed heavy products downward into the heavy products outlets
13, which are here shown partially covered because of the overhang
of the output deflector wall 36. The drive shield wall is shown at
35. This wall is actually attached to the top disk impeller, but is
added here for clarity. A gas vent 92 and a drive shield wall brace
93 are also shown. The drive shield wall brace 93 aids in the
attachment of the drive shield wall to the top disk impeller. If a
similar brace and attachment is also built into the disk impeller
for the output deflector wall 36, then the disk impeller design can
be made to be interchangeable; usable for either the top or the
bottom disk impeller.
The optional annular crossflow filter inset into the bottom disk
impeller is shown at 54, which can be used to remove fluid from a
sludge as discussed and shown in cross section in FIG. 2. A fuller
description of this annular crossflow filter in a radial
counterflow reactor can be found in the applicant's U.S. Pat. No.
7,757,866 entitled "Rotary Annular Crossflow Filter, Degasser and
Sludge Thickener."
At the periphery of the disk, a drive track 30 engages the gear
teeth of the drive wheel 29 which is driven by a motor 28, or a
sleeper wheel such as 33 which has a sleeper wheel support 34. The
drive can be a gear drive, a belt drive, a chain drive, or a
friction drive, as needed for the application requirements,
including noise, speed, and torque.
FIG. 6 shows a side view cross section of the bottom disk impeller
73 of FIG. 5, drawn to the same scale, as also shown in FIG. 1. The
bottom disk impeller 6 has an axial feed conduit 3 and an axial
feed port 4 where the feed enters underneath the baffle 5. A motor
28 drives a drive wheel 29 which engages a drive track 30 to rotate
the disk impeller 6 around the axis of rotation 10, stabilized by
sleeper wheels such as 33 and other supports such as sleeper wheel
support 34 and a base support 27. The heavy products exhaust port
is shown at 13. The disk impeller vanes 51 and the baffle vanes 52
as well as the crossflow filter 54 are also shown in FIG. 2. In the
peripheral pinch section b are the rugose ridges 56. Further toward
the periphery are the output deflector wall 36 and the drive shield
wall 35 with optional gas vents 92. A drive shield wall brace 93
can be built into a generic disk impeller design to enable
attachment of the disk shield wall to the top disk impeller.
FIGS. 7-15 show the successive rotation positions of a set of four
straight vanes on two counter-rotating disk impellers. Each figure
represents a rotation of 10.degree., so they make a repeating cycle
of 90.degree.. The direction of rotation for the top disk impeller
is at 8, and the direction of rotation for the bottom disk impeller
is shown at 9. The location of the edge of the baffle is at 78. A
straight vane on the bottom disk impeller is shown at 96, and a
straight vane on the top disk impeller is at 97. The successive
positions for these vanes are shown in each figure, and the parts
representative of the top disk impeller are shown with dashed
lines. The intersection points of the vanes form eight radial axes,
such as at 82, which are the organizing axes for the sink flow.
Liquid Impellers
FIGS. 18-19 show another example of a photobioreactor, featuring
liquid impellers, which is especially useful for aquaculture and
for UV disinfection. FIG. 18 shows a top view of an array of jets
to create a moving liquid disk impeller. Preferably this array is
static, and only the liquid moves. The liquid is fed through a
network of supply pipes. An example of a main supply pipe is shown
at 101, and 102 shows a branch supply pipe. An example of a liquid
jet nozzle is at 103. When liquid such as water is forced through
this nozzle, it makes a jet area of water pressure 104 which, in
combination with the flow from the other jets, creates an overall
direction of flow 105 for the liquid layer, forming a liquid
impeller disk. Preferably the jets should be in a planar
arrangement, parallel to the surface of the water, and the jet
nozzles are configured to spray a pattern which spreads more
horizontally than vertically, to fill in the liquid impeller layer
more completely and to keep it from becoming too thick.
In addition to the supply pipes spraying into the liquid impellers,
preferably there are also drain pipes. Drain inlets 106 feed into
drain pipes 107 which lead back to a central drain 108, which is
distinct from the central supply pipe 109. An axial exhaust pipe
110 takes out the sink flow products from the workspace. Support
frame members 111 keep the pipes and jets from becoming distorted
or out of place, and support floats 112 can relieve their weight. A
peripheral wall 113 sets a boundary for the photobioreactor.
FIG. 19 shows a cross section of two liquid impellers in the
photobioreactor. The top liquid impeller 114 is created by jets
from fluid such as water carried by main supply pipes such as at
101, fed by a central supply flow 119, creating an overall
direction of flow 8. In this case the upper boundary of the upper
impeller is equal to the surface of the water. The bottom liquid
impeller 115 is created by a similar array of pipes and jets, but
pointing in the opposite direction, so as to produce an opposite
direction of rotation 9 in the liquid impeller. Oppositely flowing
turbulence 116 extending from the boundary layer into the shear
layer in the workspace 11 creates a vortex network, with a sink
flow of lighter products 17 being drawn into the central exhaust,
while a flow of heavier products 15 flows from the periphery. A
network of drain pipes 107 is preferably also present, leading into
a central drain outlet 120. A support float 112 helps manage the
weight of the pipes, and the peripheral wall is shown at 113. The
liquid impellers can be used within a cylindrical tank or in a pond
or lake which is larger than the width of the array of jets. One
liquid impeller can also be used by itself at some distance below
the surface, allowing the surface of the water and the liquid
impeller to define the workspace.
Radiant energy 41 is applied in this case by sunlight shining
through the transparent water to encourage growth in the workspace.
The liquid impellers can introduce nutrients such as food and
beneficial gases into the workspace, by first dissolving these
components into the water carried in through the supply pipes. The
drain pipes can help draw out any waste products that find their
way into the liquid impeller layer. The liquid impellers can also
help regulate temperature in the workspace. For example, on a hot
day, the upper impeller layer can be supplied with colder water,
which will diffuse downward and cool the workspace.
Aquaculture can include the cultivation of many different types of
organisms, such as algae, shrimp, fish, oysters, and seaweed,
either alone or in combination. The younger or weaker organisms
would be more likely to be passively carried by the vortices
created in the workspace, but the larger or stronger mobile
organisms would be able to be actively able to swim into the disk
impellers themselves, where they could have more direct access to
food in the liquid impeller layer, with less competition than in
the workspace. This self-separation of organisms could aid in the
harvesting of the more mature individuals.
Biochar Processor
Another example of a radial counterflow reactor with applied
radiant energy is used for the processing of biomass for biochar,
bio-oil, and combustible gas. In this case the feed 1 is different,
but the general design of FIG. 1 is the same, with the applied
energy 41 absorbed into the feed 42 in the workspace 11 being
infrared or heat energy heating the disk impellers 6, 7, which are
made of a refractory material that can resist heat, pressure and
wear. The heating can be done by external means, such as flames
heating a portion of the disk impeller as it passes, or internal
means, such as heating coils built into the rotating disk
impellers. The combustible gas output of the process can be burned
to help supply this heat.
A wide variety of cellulosic biomass feed stocks can be used,
including wood chips, sawdust, switchgrass, bagasse, corn stover,
plant cuttings, seaweed, and algae cake, and other biodegradable
waste. The feed should be ground before it is input into the
bioreactor to enable it to be churned by the turbulence in the
workspace, and dried to reduce the energy needed to convert it.
The biomass feedstock is churned and heated in the workspace 11 of
the radial counterflow reactor, where it undergoes thermal
decomposition in an oxygen-starved environment, forming biochar and
gaseous products that comprise bio-oil and syngas. The pyrolysis of
triglycerides and other organic compounds in the feedstock forms
carboxylic acids, alkans, alkenes, aromatics, and other volatile
compounds that can be condensed into bio-oil. Syngas is comprised
of hydrogen and carbon monoxide. In addition, there will be steam
and other gaseous. The biochar may contain potash and other
compounds, depending on the feed. More applied energy 41 applied to
the bioreactor for higher temperatures will create more
gasification and less char. The infrared energy can come from
heated disk impellers, or heated sand mixed with the feed, such as
is used by BTG-BTL in their design for a rotating cone reactor. The
pyrolysis can be fast pyrolysis, for a higher proportion of bio-oil
output, or slow pyrolysis, for more biochar out. The present design
for a bioreactor will be more efficient in the processing because
of the high turbulence and rapid stripping of the light products
from the feed.
In the workspace 11, the pyrolysis of triglycerides and other
organic compounds in the feedstock forms carboxylic acids, alkans,
alkenes, aromatics, and other volatile compounds, which comprise
the light products stream 99. Producer gas, a more complete
gasification product created by even more heat and pressure, is
comprised of carbon monoxide, steam, hydrogen and other compounds,
and is useful for producing fuel and chemicals. The biochar product
is useful for soil remediation and carbon sequestration, and also
can be burned as a fuel.
FIGS. 16 and 17 shows examples of sets of flows for a radial
counterflow reactor, showing the outline of a disk impeller 7, the
axial exhaust port 18, the heavy products flow 98 toward the
periphery, and the inward light products sink flow 99, as separated
by a vortex network 100. In FIG. 16, for a radial counterflow algae
photobioreactor, the heavy products flow 98 comprises heavy
products with more specific gravity than water in the feed, such as
algogenic organic matter (AOM), senescent algae, and flocculated
algae. The light flows would be the components with less specific
gravity, such as gases, including oxygen and excess CO.sub.2 and
extruded lipids. Increasing the rotation speed of the disk
impellers as well as the suction at the axial exhaust port 18 would
increase the radial counterflow separation effects, to make healthy
excess algae that is crowding the workspace also move outward. When
the central suction is decreased and the rotation speed is
increased, the net effect is to clear out the workspace, for
cleaning or restocking. In FIG. 17, the heavy products for a
biochar reactor would include biochar, and the light products would
include bio-oil, volatile organic compounds (VOCs) and steam.
The radial counterflow reactor with applied radiant energy of this
disclosure has here been described for its use as an algae churn,
in aquaculture and as a biochar oven. However, it will be
appreciated by those skilled in the art that a continuous separator
of this type, making use of applied energy to transform the feed
while simultaneously separating the byproducts, can find use in
other applications, such as chemical engineering, refining, and
food processing.
For example, radiant energy in radial counterflow can aid in
drying, cleaning or processing solids while simultaneously
extracting vapors and gases, or other continuous processing with
centrifugal force and heating. It can also be of use in
classifying, separating and assorting solids with heat treatment,
or with separating or classifying gases and liquids by induced
swirl and rotational hydrodynamic extraction. The radial
counterflow reactor with applied radiant energy is also of use as a
pump where one fluid is pumped by contact or entrainment with
another within a rotary impeller, or by using one or more jets.
While the embodiments of the present invention have been
particularly shown and described above, it will be understood by
one of ordinary skill in the art that various changes in form and
details may be made therein without departing from the spirit and
scope of the present invention as defined by the following
claims.
* * * * *
References